The cassette housing of a video tape cassette, for example, of the VHS type, is provided with a hinged front panel as a cover, which protects the magnetic tape of an unused cassette from dirt. The front panel opens when the cassette is placed in the video recorder. In order to prestress the opening and locking device, there is an axle positioned on the inside of the front panel covering the side, which axle bears a spring coil and the long spring leg of which is positioned on the front panel. This is only the case with preassembled springs in the front panel, otherwise, the support takes place in the upper part of the housing. The front panel is at the same time maintained in a closed state by a locking plate. Small coiled spring (DE 28 37 889) or a plate spring (DE 28 37 890), which on the one hand act on the locking plate, and on the other hand are supported on a fixed wall of the housing, are used for the locking device. The two spring combinations operate perfectly, their disadvantages, however, can be easily recognised, for example, a high number of parts for the locking device, costly testing assembly, construction, which takes place in successive sections. In U.S. Pat. No. 4,466,583 and DEGM 81 21 098 a sprayed on plastics material spring for the locking plate is described in each case, which reduces the number of parts, as mentioned above. In both cases, the plastics materials spring is sprayed on in the area of the hinged axle, while the free end of the spring is positioned on the housing wall, which seals off the space behind the locking plate. Since the centre of rotation and the point of application of force are positioned relatively far apart from each other, material fatigue is to be expected after a certain time owing to the relatively great spring deflection when opening the locking plate, when on moving the spring, the elastic deformation area is left. For achieving the necessary spring forces, a correspondingly thin material cross section must be selected for the plastics material spring, which, however, also impairs the injectability.